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jrd hybrid jetting issues
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Posted by: 800screws

i can't get this thing to run right. i've gone up and down with mains, needles and pilots. it runs fine and about 5 min of riding maybe less, it boggs heavy and runs like it doesn't have enough fuel. i'm at the 4th clip on the needle, 42 or 45 pilot, and i just went up to a 195 main gradually going up from a 170. it starts right up and seems to respond to throttle movements fine for about a lap. then it boggs coming out of a turn or any time it goes from idle back on the gas. it takes numerous twists of the throttle to get it to rev back up, but it will not run right till after it sits for alittle. any ideas... i think i'm going to bring it to the shop. i wasted at least 4 days on it and have no clue.
i also had the engine rebuilt with a new piston and valves. so i know it's a carb issue. the carb also has a boyesen acc. pump cover.

Posted by: ss440ex

Try a 45 or 48 pilot jet
190 sounds way rich.... try a 165-168 main
Keep the needle clip in the middle....
Air filter clean? No intake system restrictions,kink in air box to carb boot/hose !?!??
??Tank lid venting?

With that big of a main jet and a lot of throttle-accerator pumping it may be loading up.

Just a few ideas,
Keep us posted!!!!

Posted by: 800screws

i tried a 155 also. it did the same thing...

Posted by: ss440ex

A 155 is close but its not a 165!!!
Sounds like a carburator issue some where.
Everthing install correctly after the rebuild??
Boots all tight,no paper towels stuffed any where?

Posted by: 800screws

i brought it to my local shop. i've wasted too much time and have a 3 day weekend coming up.

Posted by: ZRider400

Id trade you my YFZ for it

Posted by: 800screws

lol, if i trade it, it will be for a 2 stroke!

Posted by: hontrx265r

I know you brought it to the shop, but definetly check for air leaks if you can't figure it out. However I just want to let you know I was running around the same jetting with that pipe and all on my 426 with around a 205 to 210 main. you get on a yfz forum and they are running smaller jets. I thought maybe I was missing something so I started leaning it out, I mean its a smaller motor right? well wrong My 426 was starving without those big mains and ran great when it had them. Basically just trying to say, yfz's aren't 426's and bike 426's don't have the kind of airflow that hybrid does. Don't be afraid to try to go up, rich doesn't hurt, during testing.

Posted by: 800screws

i agree, i was posting on another 426 forum, and they said going high with the main was too rich. i kept telling them it was a hybrid quad...i mean the airbox is so exposed with the jrd one and the silencer is so short, i kinda thought it wasn't too much with the 195. it did run better with it. thanks for the input.

Posted by: atvfreak400

mine was bogging bad and I tried everything ,so I had heard that if you wired the acc pump that may fix it and low and behold the thing works great know no bog just arm pulling power,can't beat a hybrid for power.

Posted by: 800screws

got it going! it is freakin' great. never rode a quad like this before. tons of smooth power, great suspension. flies straight. i am hitting 3rd gear doubles in second with this motor...

Posted by: spent21

what was the problem?

Posted by: 800screws

i'm kinda ashamed to say, but somehow the gas that was in there when i bought it, was 1/4 water! and had enough crap floating around to look like a sea monkey farm! i guess u should always check the basics.

Posted by: Mean250r

quote:
Originally posted by 800screws
i'm kinda ashamed to say, but somehow the gas that was in there when i bought it, was 1/4 water! and had enough crap floating around to look like a sea monkey farm! i guess u should always check the basics.

ha u must of laughed when you found that out

the shop prob charged you like 2 g's to change the fuel

Posted by: 800screws

no, the guy at the shop is my cousin's husband, so lucky for me it's free, otherwise who knows!

Posted by: broke

We learn from our mistakes with things like that. I won't get in to the details but I now drain the tank and the bowls before I tear a motor apart.

To tell you the truth, if I let 110 sit in my tank for more than two weeks, it just becomes lawnmower fuel.

Posted by: 800screws

i definately will check from now on! the only crappy thing is, i got to ride the quad once instead of 4-5 times before this season is over.